Anti-diabetic potential assessment of aqueous and ethanol extracts of arrow poison (Strophanthus hispidus) plant stem bark in Wistar male rats

Diabetes mellitus is a chronic disease, for which there is no known cure except in some specific situation. The available orthodox drugs used for its management are having disadvantages. The aim of this study is to evaluate the anti-diabetic potential of aqueous and ethanol extracts of Strophanthus hispidus (SH) stem bark in Wistar male rats. Diabetes mellitus was induced by intraperitoneal injection of streptozotocin (55 mg/kg). Blood glucose concentrations, serum α-amylase and lipid profile of normal and diabetic rats were monitored for 12 weeks. The rats were treated with 250 mg/kg of aqueous and ethanol extracts of Strophanthus hispidus respectively. Dose-response study was also carried out. The results revealed significant (P<0.05) progressive decrease in fasting blood glucose concentration on the 2nd-12th weeks and 4th-12th weeks in normal and diabetic-treated rats respectively. Total cholesterol, LDL and TG levels were lowered significantly (P<0.05) by the extracts in normal and diabetic treated rats, whereas HDL levels (17.6±0.50 mg/dl) (aqueous) and (21.4±1.28 mg/dl) (ethanol) were elevated in diabetic treated rats. The activity of serum α-amylase was also elevated by the extract in diabetic treated rats. These findings indicated that SH showed hypoglycemic, anti-hyperlipidemic and anti-diabetic activities. These findings may be connected with the presence and amount of phytochemicals in the plant.Keywords: Anti-hyperlipidemic; diabetes; gavage; hypoglycemic; phytochemical

Safety assessment of Uvaria chamae root extract: acute and subchronic toxicity studies

Background: Uvaria chamae is a medicinal plant that is used in many parts of the world in the treatment of diabetes, and other diseases. However, research is needed to ascertain the beneficial and adverse effects of the consumption of the extract. In this study, we evaluated the acute and subchronic oral toxicity and safety of the aqueous root extract of Uvaria chamae in Sprague-Dawley rats.Methods: In the phase one of the acute toxicity study, the aqueous extract of the root was administered in single doses of 10, 100 and 1000 mg/kg body weight. In the phase two, the extract was administered in single doses of 600, 2900 and 5000 mg/kg body weight. In the sub-chronic toxicity study, the extract was administered at doses of 200, 500, 1000, 2000, 3000 and 5000 mg/ kg body weight/day for 28 days.Results: The acute toxicity study showed the LD50 of the extract to be above 5000 mg/kg body weight. In the subchronic toxicity study, oral administration of the extract induced a significant (p < 0.05) increase in monocytes count and platelets. There was a significant increase (p<0.05) in AST at 5000 mg/kg compared to the other concentrations administered. At 2000 mg/kg of extract the ALT level was significantly (p<0.05) elevated compared to control and the lower concentrations, while the ALP was significantly (p<0.05) reduced at the doses of 200, 500, 1000, and 2000 mg/kg when compared to control and the other concentrations. There were no significant changes in total protein and albumin at the different doses of the extract. Moreover, the Uvaria chamae extract did not significantly alter kidney function parameters such as creatinine, BUN, Na+, K+, HCO3- and Cl- in comparison to control. Histopathological evaluation showed mild vascular congestion and infiltrates of lymphocytes in the liver and kidney. We also noted well-formed islet cells of Langerhans in rats administered doses ≤ 1000 mg/kg body weight of the extract.Conclusion: Data from the study showed that the consumption of the extract at any level in the management of diseases may have potential health benefits for the management of anemia.Keywords: Aqueous root extract; Uvaria chamae; Kidney; Liver; Pancrea

Long term hypolipidaemic and anti-atherogenic effects ofCarica papaya Linn. administration on normal rabbits

Carica papaya Linn. (Caricaceae) is commonly called paw-paw and papaya. It is used widely in the tropics and sub-tropics as food and medicinal plant. Various parts of the plant are used in folkloric medicine for the treatment of indigestion, asthma, beriberi, jaundice, as well as for wound dressing. This study was designed to assess the long term (24 weeks) effects of daily oral administration of C. papaya aqueous leaf extract (at 200 mg/kg body weight) on the serum lipid profile and other atherogenic indices of normal rabbits. Total cholesterol, total triglycerides, LDL-cholesterol, HDL-cholesterol, atherogenic and coronary risk indices were monitored periodically for 24 weeks. Administration of C. papaya leaf extract caused significant reductions in total cholesterol, triglycerides and LDL-cholesterol. Also, from week 10 of this study, HDL-cholesterol concentration increased in the C. papaya treated rabbits. Atherogenic and coronary risk indices were not altered. The antihyperlipidaemic effect observed in this study may be attributed to the nutrients and phytochemicals found in C. papaya.Keywords: Lipid profile; Atherogenic index; Coronary risk index; Carica papaya; Medicinal plants; Hypolipidaemi

Anti-diabetic, anti-hyperlipidaemic and anti-oxidant effects of saponins fractions of Irvingia gabonensis stem bark in streptozotocin diabetic female rats

Background: Irvingia gabonensis aqueous stem bark extract possesses significant long term (24 weeks) hypoglycaemic /antidiabetic, hypolipidaemic and antioxidant effects. Preliminary phytochemical analysis revealed the presence of saponins in I. gabonensis stem bark. Saponins from various plant sources have been shown to also possess these effects.Objectives: The aim of this study was therefore to ascertain the contribution of I. gabonensis total saponins fractions (ITSF) to the observed antidiabetic, antihyperlipidaemic and antioxidant effects of the crude aqueous extracts.Methods: ITSF was extracted from I. gabonensis stem bark by sequential solvent extraction and chromatographic methods. Twenty (25) Wistar rats in five groups (normal control, diabetic control, 10mg saponins/kg b. w. treated diabetic rats, 20mg saponins/kg b. w. treated diabetic rats and 40mg saponins/kg b. w. treated diabetic rats) were used in this study. After twenty-eight (28) days of ITSF administration; the fasting blood sugar (FBS), serum lipid profile and oxidative status of streptozotocin-diabetic female rats were assessed.Results: I. gabonensis saponins slightly reduced the FBS of STZ diabetic female rats. Higher concentrations of saponins (20 and 40 mg/Kg body weight) caused reductions in serum total cholesterol, LDL-cholesterol and triglycerides, while HDL-cholesterol concentrations were significantly (P<0.05) increased in the saponins treated diabetic female rats (TDFR). The higher concentrations of the saponins caused significant (P<0.05) reductions in serum and tissue MDA concentrations, while SOD, CAT, GST and GSH levels were mostly increased in the TDFR.Conclusion: Our findings showed that ITSF had only a marginal short-term anti diabetic effect, but exhibited substantial anti-hyperlipidaemic and anti-oxidant effects. It is possible that the phytochemicals found in I. gabonensis bark, including saponins, may act synergistically to exert its anti-diabetic effect; there is also the possibility that it may take a longer period of time for the anti-diabetic effects of I. gabonensis saponins to become evident.Keywords:  Irvingia gabonensis; Saponins; Anti-diabetic; Anti-hyperlipidaemic; Anti-oxidan